There has been known a technology of displaying an object to be arranged by displaying a depth direction of the object and performing an interference check so that a plurality of objects is not arranged within the same space when the object is edited within a virtual three-dimensional space (see, e.g., Japanese Laid-Open Patent Publication No. 08-129655). According to such a technology, it becomes possible to easily and efficiently execute editing such as arrangement, movement, rotation, and alignment of an object within a virtual three-dimensional space while visually recognizing the editing on a two-dimensional display.
Also, there has been known a technology of making the color of a designated activated drawing opposite to other overlapping drawings when the designated activated drawing partially overlaps with other drawings in an element such as a line segment, (see, e.g., Japanese Laid-Open Patent Publication No. 06-290226). According to such a technique, in performing designing and plotting using the CAD, even when there exists a drawing overlapping with a designated activated drawing, it is easy to distinguish the drawings from each other, thereby improving the operability of the CAD.
Further, there has been known a technology of asking for a radio interference situation based on information on the location, height, and shape of a predetermined building, and the location of a given radio wave source using data stored in a three-dimensional city database (see, e.g., Japanese Laid-Open Patent Publication No. 2000-123198). According to such a technique, it becomes possible to perform a more precise simulation by considering a radio wave diffraction of a building in the height direction, and considering a radio wave interference over the entire side face of the building.
Related technologies are disclosed in, for example, Japanese Laid-Open Patent Publication Nos. 08-129655, 06-290226, and 2000-123198.